There is only one alkyne that forms an aldehyde when it undergoes the mercuric-ion-catalyzed addition of water. What is this alkyne?

1 Answer
Feb 17, 2015

The alkyne is ethyne.

The mercury(II) catalyzed hydration of an alkyne first forms an enol, which then tautomerizes to the more stable carbonyl compound.

![Chemical reaction with alkyne from http://www.meritnation.com](http://www.meritnation.com/img/shared/discuss_editlive/4255118/2013_03_01_17_32_34/abacesrl888214422089730600.png)

In the hydration of ethyne, the intermediate product is ethenol.

The tautomeric rearrangement of ethenol results in the formation of ethanal.